Even if you did manage to eat that much on one day, you surely wouldnt even come close the next. I called BS on that article the second I read it. I think the article is almost a setup for energy drink sales.
Swimming with a full stomach is impossible. It hurts. Even if he has an extreme metabolism, he would be spending a lot of time in the can.
The diet is not realistic, I don't care who you are. You could be morbidly obese and have a hard time eating like that.
You would be a plugged-up lethargic pig.